* Astronomy

Tree stumps at the feet of Western Canadian glaciers are providing new insights into the accelerated rates at which the rivers of ice have been shrinking due to human-aided global warming.
Geologist Johannes Koch of The College of Wooster found the deceptively fresh and intact tree stumps beside the retreating glaciers of Garibaldi Provincial Park, about 60 km north of Vancouver, British Columbia. What he wanted to know was how long ago the glaciers made their first forays into a long-lost forest to kill the trees and bury them under ice.
To find out, Koch radiocarbon-dated wood from the stumps to see how long they have been in cold storage. The result was a surprising 7000 years.

"The stumps were in very good condition sometimes with bark preserved" - Johannes Koch , who conducted the work as part of his doctoral thesis at Simon Fraser University in Burnaby, British Columbia. Koch will present his results on Wednesday, 31 October 2007, at the Geological Society of America Annual Meeting in Denver.

The pristine condition of the wood, he said, can best be explained by the stumps having spent all of the last seven millennia under tens to hundreds of meters of ice. All stumps were still rooted to their original soil and location.

"Thus they really indicate when the glaciers overrode them, and their kill date gives the age of the glacier advance" - Johannes Koch.

They also give us a span of time during which the glaciers have always been larger than they were 7000 years ago until the recently warming climate released the stumps from their icy tombs.
Koch compared the kill dates of the trees in the southern and northern Coast Mountains of British Columbia and those in the mid- and southern Rocky Mountains in Canada to similar records from the Yukon Territory, the European Alps, New Zealand and South America. He also looked at the age of Oetzi, the prehistoric mummified alpine "Iceman" found at Niederjoch Glacier, and similarly well-preserved wood from glaciers and snowfields in Scandinavia.
The radiocarbon dates seem to be the same around the world, according to Koch. It's important to note that there have been many advances and retreats of these glaciers over the past 7000 years, but no retreats that have pushed them back so far upstream as to expose these trees.
The age of the tree stumps gives new emphasis to the well-documented "before" and "after" photographs of retreating glaciers during the 20th century.

"It seems like an unprecedented change in a short amount of time. From this work and many other studies looking at forcings of the climate system, one has to turn away from natural ones alone to explain this dramatic change of the past 150 years" - Johannes Koch.

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Ancient Records Help Test Climate Change
A librarian at this 10th century monastery leads a visitor beneath the vaulted ceilings of the archive past the skulls of two former abbots. He pushes aside medieval ledgers of indulgences and absolutions, pulls out one of 13 bound diaries inscribed from 1671 to 1704 and starts to read about the weather.

"Jan. 11 was so frightfully cold that all of the communion wine froze.  Since I've been an ordained priest, the sacrament has never frozen in the chalice" - entry from 1684 by Brother Josef Dietrich, governor and "weatherman" of the once-powerful Einsiedeln Monastery.

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Future ice ages may be delayed by up to half a million years by our burning of fossil fuels. That is the implication of recent work by Dr Toby Tyrrell of the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton.
According to New Scientist magazine, which features Dr Tyrrell's research this week, this work demonstrates the most far-reaching disruption of long-term planetary processes yet suggested for human activity.
Dr Tyrrell's team used a mathematical model to study what would happen to marine chemistry in a world with ever-increasing supplies of the greenhouse gas, carbon dioxide.
The world's oceans are absorbing CO2 from the atmosphere but in doing so they are becoming more acidic. This in turn is dissolving the calcium carbonate in the shells produced by surface-dwelling marine organisms, adding even more carbon to the oceans. The outcome is elevated carbon dioxide for far longer than previously assumed.

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About twice as many Atlantic hurricanes form each year on average than a century ago, according to a new statistical analysis of hurricanes and tropical storms in the north Atlantic. The study concludes that warmer sea surface temperatures (SSTs) and altered wind patterns associated with global climate change are fueling much of the increase.


A new climate study indicates that hurricanes and tropical storms became more frequent in the Atlantic Ocean during three distinct periods over the last century, as shown in this graphic. The first part of the 20th century (in white) was relatively quiet, with an annual average of 6 observed hurricanes and tropical storms. The annual average increased to 10 after 1930, and then reached 15 from 1995 to 2005 (in darkest shading). This graphic shows both the total number each year (blue line) and the nine-year running average, calculated from four years back through four years ahead of a given year. Called a running mean, this method smoothes out year-to-year variability to reveal the long-term trend. The new research associates the increasing storms with rising sea-surface temperatures. [ENLARGE] (Illustration by Steve Deyo, ©UCAR.)

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